[ODE] rotation matrices

Hi,
I'm trying to attach a system of points (specifically not ODE
constructs) to an ODE body by means of updating the system's position
at each time such that any changes in position of the ODE body cause
the system to move accordingly. In order to completely constrain the
system I also need to update its rotation relative to the ODE body
such that it appears to be fully 'attached'. I was wondering what the
easiest way would be to update the position of these points so they
stay the same relative the ODE body. I've tried using the angular
velocity of the body to calculate necessary velocities for the
points, but could not get that too work. Is there an easy way of
using the rotation matrices to accomplish this?
Thanks,
- Floris